Multiwall bag of paper or similar material



June 28, 1938. oppg, 2,122,061

' MULTIWALL BAG OF PAPER .OR SIMILAR MATERIAL Filed Sept. 21', 1954 sSheets-Sheet 1 TTEnLb a/ z b I (Z) L='-L r-:.

4 rfw l a mw Edgar Hoppe June I E HOPPE muunwm, age OF PAPER OR SIMILARMATERIAL Filed Sept. 21, 1954. 3 Sheets-Shee't 2 gn/uxz/vviod- EdgarHoppe Patented June 28, 1938 UNITED STATES PATENT OFFICE 2,122,061MULTIWALL BAG OF PAPER OR SIMILAR MATERIAL Edgar Hoppe, Amsterdam,

to St. Regis Paper Company,

Netherlands, assignor New York, N. Y.,

In Germany 7 Claims.

to pasted end bags, but particularly to multl-ply bags of paper, orsimilar material, in which one or both ends are closed by arrangingopposite plies in stepped formation and adhesively connecting theseplies together.

Existing methods of forming such bags differ from each other mainly inthe cutting of the ends of the separate bags. In case of one of theknown methods the separate inside layers project 10 in a step-likemanner over the outside layers, or

on the contrary, they are shorter than the outside layers also in astepped order.

Another method of manufacturing bags, which in comparison to the abovementioned method represents a considerable improvement, provideslongitudinal edges stepped on one side flap on the inside and on theopposite side flap on the outside. The folded end flaps of theindividual tubes in this case are of equal length, i. e. they go are notstepped.

All known methods provide, however, that the steps at the bag ends,lying opposite ,to each other, are of equal width with respect to eachother, so that when forming the bag bottom by folding the side flaps,the free part of each separate longitudinal edge is placed on the freepart of the opposite longitudinal edge of the same tube and pastedtogether.

This separate interpasting, at least of the longitudinal edges of eachindividual tube, was heretofore considered absolutely necessary in orderto obtain a secure and strong closure. Such method requires, however,precision and accuracy in regard to laying the individual layers one tothe other before they are formed into tubes. However, it is a simplematter-for the paper layers to shift with reference to each other duringthe formation of the tubes, so that the steps do not register. 1

It has been found, however, that the pasting of each longitudinal edgeindividually with the opposite lonigtudinal edge of. the same tube isnot so important in regard to the strength of the closure as it wasconsidered previously, and that it is not essential to make the steps ofthe individual paper plies or individual tubes absolutely equal to oneanother in case that it is to be stepped at all. Furthermore, it hasbeen found that deviation from the usual way of forming this kind of abag even obtains a stronger pasting of the bag bottom.

It is possible, therefore, to give different widths to the oppositeindividual steps and achieve a considerable simplification of themanufacturing 5 process and at the same time to retain and even Thisinvention relates April 21, 1934 increase the advantages offered bystepped bags generally.

For example, it is possible to lengthen the inside edge of alongitudinal step to such an extent that it partly or even completelycovers the opposite step of the next layer. When folded in this mannertwo or more steps of the opposite side arecovered whereby eventually thenext to the outside following edge does not need at all to cover theopposite edge of the corresponding layer or to be pasted with it.

It has been found advantageous to make two or more steps of the onelongitudinal side equally long so that they cover one another completelyand only the inner edges project over and are pasted to one or more ofthe opposite longitudinal edges. The above mentioned examples have onlythe purpose of showing that the width of the steps or the relation ofthe widths of the steps to I each other can be actually varied to alarge extent without diminishing the advantages of the stepped bag. Itwill be understood that upon separating a bag length from the bag tube;the difference in the width of the steps always produces a correspondingformation of steps in reverse direction in the following bag length.

The strength of the bag closure produced by the above described methodcan be still increased by interpasting the.single tubes at their endseither throughout the whole or part of their circumference, therebycompletely abandoning the principle of absolute independence of thelongitudinal edges or that of the side flaps from each other, accordingto the old manufacturing methods.

This pasting may be accomplished before the bag tube is formed and isespecially important if two steps completely overlap each other, i. e.one inner step extends up to or over the height of the following step.To suit the purpose the individual tubes preferably are pasted togetherin such case not only at the side flaps, but also at the end flaps. Thelast measure has proved especially important in case of bag closureswith unstepped side flaps.

By pasting together the single paper webs before the formation of thetube, a further advantage is gained, namely that the individual paperwebs remain secure in their relative position to one another. The aboveadvantage makes the application of this measure especially advisable incase of bags, which are formed by tubes with equal sized steps.

By further developing the idea of pasting the individual paper webstogether, the invention proiii) poses in case of steppe bags of thedescribed kind, and mainly in case of bags provided with side flaps,which together with side flaps folded over t em are used on one side ofthe bag for the formation of the valve, to eliminate the fre quenttrouble of the folded flaps fallingout rather short, if no specialprecaution is taken, and therefore exposed to the danger of being blownout of the bag when it is filled. This danger is eliminated according tothe invention in such way that besides the pasting together of the flapsthe back side of the flap which at folding forms the innermost flap, ispasted to the stepped side flaps insofar as it touches them. Thestrength of the valves is thus increased to a considerable extent.

In many cases it is desirable to lengthen the valve flap in order tosecure a still more reliable In order to attain this.-

closure of the valve. it has been proposed to provide a specialelongation of the valve flap, formed at the folding which is afterwardspasted in. The same result is attained according to the invention bythemanufacturing method described below in a much simpler and moreadvantageous manner and without additional consumption of material andwaste by separation of single bag lengths from each tive tearing of theperforation.

To enable this kind of separation it is necessary to transfer thoseparts of the above mentioned pre-cut paper web, which are stillunweakened until final cutting takes place, to the outer edges.

.It is advisable to transfer also the longitudinal glued seams of thetubes to the unstepped parts of the web. V

The lengthening of the valve is attained in such way that the outerparts of the tube forming the flaps are cut on the one side of the bagtube at a difierent level from the other side or from the middle levelof the steps, and in such way that the flaps on the side provided forthe formation of the valve are longer than on the other side. This meansthat the corresponding out is displaced with reference to the level ofthe other and results in a corresponding shortening of the adjoiningflap in the following bag length. This is, however. of no disadvantage,since the valve is formed anyway only on one side of the bag and for theformation of a simple bag closure without a valve shortened flaps aresufllcient, especially if besides the usual pasting they are pasted likethe valve flaps also along their inner sides with the longitudinaledges.

The cut separating the valve flap from the iongitudinal edges is madedeeper than the level of the shortest step of the longitudinal flaps,which enables lengthening of the valve flap at least up to theheightofthe longest step. The surface of contact between thelongitudinal edge and the valve flap is thereby substantiallyv enlargedand the safety of-the valve closure, especially when pasting these partsin the aforemen tioned manner, considerably increased.

The final result is that by these means considarable lengthening of thevalve flap is attained which allows a proper valve formation in the caseof wholly or partly interpasted edges of the individual paper webs. Theapplication of the above described idea is, however, not restricted onlyto the bass with stepped longitudinal edgesand unstepped side flaps, butalso is applicable to such bags, which are not stepped at all, i. e. theindividual tubes of which are cut in their whole circumference equallyand only the side flaps are separated from the part forming thelongitudinal edges by cuts and on the other hand also to bags steppedall round as well as to singleply bags of the annexed drawings whichillustrate for example some of the described bag forms and which arecomprehensible without further explanation.

Fig. 1a is a plan view showing an unfolded closure forming part of thebag having stepped side flaps, the steps of which are unsymmetrical onopposite sides being separated from the folded end flaps by alongitudinal cut.

' Figure 1b is a view similar to Fig. 1a showing one side flap foldedalong the line g-h.

Figure 2a is a plan view of a bag end similar -to that shown in Fig.10., but having the flap elongated on the side forming a valve flap.

- Figure 2b is a plan view of a bag end similar to Fig. 2a except thatthe plies are not stepped.

Figs. fia'ancl 3b are plan views of a portion of a bag tube lengthshowing the cutting lines for effecting the valve flap shown in Figs. 2aand 2b.

Fig. 4 shows the shape of the ends of the unfolded individual tubes of athree wall bag with an elongate valve flap.

In the forms of the invention shown on the drawings, it is of noimportance whether thebag is provided with gussets or not, or whether itis an open mouth bag or a valve bag, with the exception of suchimprovements, which refer to the valve or its formation. v

The Figures la. and 1b demonstrate the different widths of the opposedsets of helps I, 2, 3 of a three-wall bag'tube, and the overlapping ofiongitudinal edges, after the side flaps 4 and 5, which latter are ofequal width, have been folded inwardly.

In the upper part of Fig. la the visible steps of the longitudinal edgesi, 2 and 3, and in the lower part of the figure the invisible stepsoutlined with dashed lines and marked with figures in parentheses areshown; also steps (2) and (8). covered by the innermost longest step(i). After folding the lower side flap inwardly along the folding beingdisposed below and the steps (2) and (3) being disposed over the stepi). If the side flap shown in the upper part of the figure is foldedinwardly along the line (i-Jc), it is clear that the wider step (i)comes to lie over the steps i and 2 of the opposite side and even partlycovers the step (3). In order to show the separation lines the lines ofthe single steps are marked a-b,

0-42 and e-f, the lines resulting after folding the steps are marked(it-4i), (c-d) and (6-4).

The Figures 2a and 2b are comprehensible line (g-h), the severallongitudinal edges of the 1 plies are rendered visible, theinnermost-step i) v a bag bottom of an entirely unstepped bag shown onFigure 21),, only the upper layer of the unfolded closure, 1. e. theinner layer of the side flaps is visible.

In the unseparated bagtube shown on Figs. 3a and 3b, the separatinglines are indicated by the reference numerals 6, I and 8. 9 are cuttinglines lying in the middle level, near the outer edge on the side notintended for valve formation, and III are cutting lines shifted from themiddle level on the side intended forvalve formation, both linesextending longitudinally of the bag tube. It will be seen that thecutting lines ll extending longitudinally of the bag tube and separatingthe end flaps from the side flaps extend up to the level of the shorteststep.

Fig. 4 shows the cutting of the ends of the unfolded individual tubes ofa three-wall bag, the steps of the side flaps being marked I, 2 and l.The valve flap is indicated at 5, only one layer being seen. On thisflap are marked with dotted lines the planes 12, which come to lieagainstthe side flaps and are pasted to them when the valve flap isfolded. The glued longitudinal seams ll, 14 and I5 lie as describedabove in the unstepped part of the bag, i. e., these seams terminate inthe end flaps as distinguished from side flaps.

Of course, the invention is not restricted to the above described or tothe fund bags illustrated in the drawings, but can be changed in variousrespects without departing from the spirit of the invention, especiallyas claims.

What is claimed:

1. A multi-ply bag having an end closure consisting of side flaps andend flaps, said side flaps being materially more extensive than the endflaps and having their longitudinal edges arranged in stepped relationon opposite sides, a step on one side substantially throughout itslength overlapping more than one step on the otherside at the ends ofsaid edges, and the undersurface of each step of one side flap engagingone or another step of the opposite side flap, and means to secure theside flaps together.

2. A multi-ply bag having an end closure consisting of side flapsand endflaps, said side naps having their longitudinal edges arranged instepped relation on opposite sides, the lengths of the correspondingsteps transversely of the bag on the opposed side flaps being different,and means for securing the side flaps together.

3. Multi-ply satchel bottom bag having the piles formed from sheetsunited by longitudinal addefined in the app hered seams, said seams allterminating in end flaps as distinguished from side flaps, and a valvein the end of said. bag opposed to said seams.

4. A multi-ply bag having an end closure consisting of side flaps andend flaps separated by cuts running longitudinally of the bag, said sideflaps having their longitudinal edges arranged in stepped relation onopposite sides, the lengths of the corresponding steps transversely ofthe bag on the opposed side flaps being different, the end flap on oneend being longer than the other end flap, the longer end flap, beinginside of and free from adjacent flaps for securing the side flapstogether.

5. A multi-ply bag having an end closure consisting of side flaps andend flaps separated by cuts running longitudinally of the bag, said sideflaps having their longitudinal edges arranged in stepped relation onopposite sides, a step on one side overlapping more than one step on theother side, the lengths of the corresponding steps on opposed side. napsbeing diiferent, and means for securing the side flaps together.

6. A multi-ply bag having an end closure consisting of side flaps andend flaps separated by cuts running longitudinally of the bag, said sideflaps being materially more extensive than the end flaps and havingtheir longitudinal edges arranged in stepped relation on opposite sides,the step on one side substantially throughout its length overlappingmore than one step on the other side at the ends of said edges, and theunder surface of each step of one side flap engaging one or another stepof the opposite side flap, the end flap on one end being longer than theother end flap, the longer end flap being inside of and free fromadjacent flaps to form a valve, and means to secure the side flapstogether.

7. A multi-ply bag having the plies formed from sheets united bylongitudinally adhered seams, an end closure consisting of side flapsand end flaps, said seams all terminating in said end flaps, said sideflaps having their longitudinal edges arranged in stepped relation onopposite sides, the lengths of the corresponding steps transversely ofthe bag on the opposed side flaps being diilerent, and means to securethe side flaps together.

. EDGAR HOPPE.

to form a valve, and means

